2013/2/25 Michael Snoyman <[email protected]> > > At that point, we've now made two changes to REWRITE rules: > > 1. They can takes a new ALWAYS parameters. > 2. There's a new, special identifier currentLocation available. > > What would be the advantage is of that approach versus introducing a > single new REWRITE_WITH_LOCATION pragma? >
Just a remark: 'currentLocation' is not a function (it's a special keyword) but behaves like one - it returns some kind of value. But it's not referentially transparent - it returns a different value depending on where it's used. This is something that I really don't expect from Haskell. So having it return `IO Location` seems therefore much better option. And if someone really wants to get the location as a pure value, (s)he can simply wrap it with `unsafePerformIO`, which signals code readers to be careful with that part. Best regards, Petr
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